Diwali dates back to ancient times in India, as a festival after the summer harvest in the Hindu calendar month of Kartika. The festival is mentioned in Sanskrit texts such as the Padma Purana, the Skanda Purana both completed in second half of 1st millennium AD but believed to have been expanded from a core text from an earlier era. The diyas (lamps) are mentioned in Skanda Purana to symbolically represent parts of sun, the cosmic giver of light and energy to all life, who seasonally transitions in the Hindu calendar month of Kartik.